Step 3.5 Flash (free)

Other chatreasoningtool_use Long

API ID: stepfun/step-3.5-flash

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Input Price
$0.10
/1M tokens
Output Price
$0.30
/1M tokens

About Step 3.5 Flash (free)

Step is StepFun AI's model series, delivering strong performance on general language tasks. The models excel at conversation, reasoning, and content generation. Step demonstrates StepFun's advancement in language model development. For developers seeking capable AI from StepFun, the series offers reliable performance.

💰
Price Ranking
#655 lowest price among 950 Chat models

Model Specifications

Context Length
256k
Max Output
256k
Release Date
2026-01-29
Capabilities
chat reasoning tool_use
Input Modalities
text
Output Modalities
text

Best For

  • Complex reasoning, math problems, multi-step logic
  • Conversations, content writing, general assistance

Consider Alternatives For

  • Image understanding (needs vision capability)
  • Simple Q&A (cheaper models available)

💰 Real-World Cost Examples

Estimated monthly costs for common use cases

Personal AI Assistant
$0.14
/month
50 conversations/day, ~500 tokens each
Customer Service Bot
$4.20
/month
1000 tickets/day, ~800 tokens each
Data Analysis Pipeline
$5.85
/month
500 analyses/day, ~2k tokens each
Calculate Your Custom Usage

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🚀 Quick Start

Get started with Step 3.5 Flash (free) API

OpenAI-compatible SDK 
from openai import OpenAI

client = OpenAI(
    base_url="https://api.provider.com/v1",
    api_key="YOUR_API_KEY"
)

response = client.chat.completions.create(
    model="stepfun/step-3.5-flash",
    messages=[
        {"role": "user", "content": "Hello!"}
    ]
)
print(response.choices[0].message.content)

Resources

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